As the country's deadliest wildfire in a century burns through Northern California, smoke-clogged air is flooding into communities across cities throughout the region, forcing people indoors and prompting health warnings.
The Camp Fire has so far killed at least 76 people, turned the town of Paradise into rubble, and left more than 1,300 people unaccounted for a week after it sparked in Butte County.
The blaze has brought unhealthy air conditions to Northern California as thick, sooty smoke moves slow enough to stall over coastal mountains, instead funneling through the Golden Gate. There is also no ocean breeze to help clear the air.
The Environmental Protection Agency's Air Quality Index was measured at 164, or "unhealthy" on Sunday morning for parts of the greater San Francisco area. The index warns that people with heart or lung disease, older adults, and children "should avoid prolonged or heavy exertion," adding that "everyone else should reduce prolonged or heavy exertion."
“Bottom line is, this is terrible,” Sam Atwood, spokesman for the South Coast Air Quality Management District, told KTVU.
Air quality readings in San Francisco and Oakland soared well above 250 on Friday, making it the worst air quality in the world compared to places like New Delhi and Beijing, which are known for having severe pollution.
"My eyes were watery and I had a tickle in my throat, so that's not good," Peter Gabriele of Livermore told KTVU.
San Francisco Mayor London Breed urged residents to remain indoors throughout the weekend and urged people to check on vulnerable groups, such as seniors.
"Ultimately during this very challenging time in San Francisco, our goal is to provide the additional resources and really just ask that we look out for one another as we get through this," she said.
The National Park Service closed several popular visitor facilities in the San Francisco area due to the unhealthy air. Sites such as Alcatraz Island, the Golden Gate Bridge Welcome Center, and Muir Woods National Monument Visitor Center in Marin County are shuttered through Monday.
Area residents have been flocking to stores to get face masks in order to shield themselves when going outside. Many stores have placed limits on how many masks people can buy in order to keep the now-popular items in stock.
"It's serious," Gail Shulman told KGO-TV. "It's gone on for days, I want to guard my family's health."
The annual Big Game between Stanford and California scheduled for Saturday was postponed two weeks because of the unhealthy air quality from the fires. Cal announced Friday that the game would be played Dec. 1 with a noon kickoff at Memorial Stadium.
President Trump visited the area on Saturday, where he walked through the ashes of a mobile home and RV park in Paradise and met with families and first responders.
"We've never seen anything like this in California; we've never seen anything like this yet. It's like total devastation," the president said.
Air quality conditions may finally improve this week, as widespread rainfall is expected to develop across the region by Wednesday, according to the National Weather Service.
The Associated Press contributed to this report.